Gang condenser



May 2, 1933- A. D. cowPERTHwAl-r 1,907,097

GANG CONDENSER Filed July 2O,r 1929 Patented May 2, 1933 UNITED STATES PATENT OFFICE ARTHUR D. COWPERTH'WAIT, OF WATERBURY,

MANUFACTURING COMPANY, 0F WATERBURY, CONNECTICUT, A CORPORATION OF CONNECTICUT CONNECTICUT, Asslenon rro scovILL GANG CONDENSER f Application filed July 20, 1929. Serial No. 379,617.

This invention relates to improvements in variable electric gang condensers. y

It is an object of the invention to provide means for equalizing the potentials of the rotors of the individual condensers and improve the shielding between condensers.

\ With these general objects in view, the invention consists in certain features, combinations, details of construction, and arrangements of parts which will first be described in connection with the accompanying drawing and then more particularly pointed out.

In the drawing:

Figure 1 is a plan View of al gang condenser constructed in accordance with the present invention;`

Figure 2 is a cross-sectional view taken as o n line 2-2 of Figure 1; and

Figure 3 is a sectional view taken as on line 3-3 of Figure 1.

Referring in detail to the embodiment chosen to illustrate the invention, the gang condenser comprises a frame having a bottom 10, side walls 11 and' end walls 12, said frame being open at the top. The frame may be composed of any suitable conducting metal, but generally brass or steel. Withn the frame a plurality of condenser units are disposed. As here shown, the condenser units comprise rotors 13, mounted on sleeves 9 fitted tightly on a common rotor shaft 14, and stators 15 mounted within and supportedby the frame but insulated therefrom. rI`he rotors and stators illustrated comprise spaced parallel plates adapted to be interleaved varying amounts upon rotation of the shaft andshaped so as to impart to the condenser a characteristic law of capacty variation. In the exemplification, the rotor shaft is journaled in the end walls of the frame and the rotors are connected electrically to said frame throughsaid shaft. One end of the shaft projects beyond its end wall for attachment of an operating device, such as a dial (not shown) or other means for rotating the shaft. The rotor shaft is preferably \pro vided with a friction brake, generally indicated at 16, for producing a regulative frictional force 'retarding rotation of the shaft.

This general form of gang condenser consufliciently struction is already known and in use. It I has been foundhowever, that there are electrostatic reactions between the individual condenser units and that the rotors of said units are not equalized as to potential, the difference being due to potential drops along the rotor shaft.

rIhe invention, in its entirety, embodies shielding means for; increasingr the air paths between the condenser units to extents substantially to inhibit electrostatic reactions between them. constructions, as here shown by way of example, shielding plates 17 of metallic conducting material are placed between the condenser units transversely across the frame. In the example, the plates are provided with slots 18 for the accommodation of the side walls of the frame, and with lugs 19 on the bottom edges serving as tenons for engaging with corresponding apertures or mortises in the bottom side of the frame. The lugs may be soldered in their apertures or otherwise secured therein. The shielding plates are thus secured in place, and electrically connected to the frame. The rotor shaft, 14, extends through openings in ,the shielding plates and, asshown, the plates project appreciably above said shaft and are large substantially to prevent reactions in the air between con- The air paths between conelectrostatic denser units. denser units are,

trostatic reactions through the air paths are practically eliminated. Although capable of some variations, for best results, the plates should extend above the shaft distances at least equal to the heights and points reached by the rotors on rotation so as to prevent straight air paths of their positions. plates overlap the in effect, increased by thev shielding plates to amounts such that elecy Although capable of various between the rotors at any veniently be accomplished by electrically connecting the rotors to the shields. Although capable of various constructions, inthat here shown as an example, the rotors are electrically connected to the shielding plates by' clips 21 which are pressed between the shields andthe ends of the rotor sleeves. As here shown, the clips are of thin sheet metal, of

bowed, resilient nature so as to be compressed in place and firmly engage the shields and sleeves to establish good electrical contacts. The clips are formed as with slots 22 in order to slip over therotor shaft into properpositions and are held in such positions by suitable means, such, for example,

-as lugs 23 on the clips which enter recesses or perforations 24 in the shields. This construction allows a clip conveniently to be slipped in place or withdrawn.

What is claimed is: A variable condenser com rising a conducting frame, a plurality o variable con- I' denser units within the frame embodying stators supported by the frame and insulated therefrom, rotors, sleeves on which'the rotors are mounted and a'- common shaft on which the sleeves are fitted, conducting shieldinor plates between condenser units and electrically connected to the frame, and bowed, resilient conducting'clips pressed between the shielding plates and sleeve ends for connecting electrically the sleeves to the plates, each clip having end portions engaging the shielding plates and intermediate portions engaging said rotors, a clip bearing on each side of each of said shielding plates and' exerting pressure on said rotors in opposite directions. v

In testimony whereof, I have hereunto set my hand.

lARTHUR D. COWPERTHWAIT. 

